EE-IoT: An Energy-Efficient IoT Communication Scheme for WLANs
EE-IoT: An Energy-Efficient IoT Communication Scheme for WLANs
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DOI：
10.1109/infocom.2019.8737625
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发表时间：
2019-04
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影响因子：
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通讯作者：
Hossein Pirayesh;Pedram Kheirkhah Sangdeh;Huacheng Zeng
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文献类型：
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作者：
Hossein Pirayesh;Pedram Kheirkhah Sangdeh;Huacheng Zeng
虽然窄带物联网 (NB-IoT) 已由 3GPP 标准化，为物联网设备提供无线互联网接入，但该服务预计需按月付费（例如每台设备每月 1 或 2 美元）。由于物联网设备数量趋于庞大，服务费将对最终用户造成相当大的经济负担。在本文中，我们利用家庭、办公室、校园和城市环境中广泛使用的现有 WiFi 基础设施，提出了一种节能物联网 (EE-IoT) 通信方案。 EE-IoT不仅可以避免最终用户的每月服务费，还可以保持物联网设备的低功耗。 EE-IoT 的关键组件是非对称物理 (PHY) 设计，它使基于 OFDM 的宽带 AP 能够在上行链路和下行链路中以低采样率 (250 ksps) 与多个基于 QAM 的窄带物联网设备进行通信。我们设计的技巧在于，每个 IoT 设备不是使用与 AP 相同的载波频率，而是将其载波频率调整到 AP 的 OFDM 信号的特定子载波，从而可以以低采样率对该子载波上的数据进行编码/解码。基于这个新的 PHY，我们提出了一种 MAC 协议来在 WLAN 中启用 EE-IoT。我们在 USRP2 无线测试台上构建了 EE-IoT 原型，并评估了其在办公楼环境中的性能。实验结果表明，一个AP可以同时服务24个物联网设备，每个物联网设备下行速率可达187kbps以上，上行速率可达125kbps以上。
While Narrow-Band Internet of Things (NB-IoT) has been standardized by 3GPP to provide wireless Internet access for IoT devices, this service is expected to come with a monthly fee (e.g., $1 or $2 per month per device). As the number of IoT devices tends to be large, the service charge will impose a considerable financial burden on the end users. In this paper, we propose an Energy-Efficient IoT (EE-IoT) communication scheme by taking advantage of the existing WiFi infrastructure that is widely available in home, office, campus, and city environments. EE-IoT will not only avoid monthly service charge for the end users but also maintain a low power consumption for IoT devices. The key component of EE-IoT is an asymmetric physical (PHY) design, which enables an OFDM-based broadband AP to communicate with multiple QAM-based narrowband IoT devices at a low sampling rate (250 ksps) in both uplink and downlink. The trick in our design is that, instead of using the same carrier frequency as the AP, each IoT device tunes its carrier frequency to a particular subcarrier of the AP’s OFDM signal, making it possible to encode/decode the data on that subcarrier at a low sampling rate. Based on this new PHY, we propose a MAC protocol to enable EE-IoT in WLANs. We have built a prototype of EE-IoT on a USRP2 wireless testbed and evaluated its performance in an office building environment. Experimental results show that an AP can serve 24 IoT devices simultaneously and each IoT device can achieve more than 187 kbps in the downlink and more than 125 kbps in the uplink.